CN110783661B

CN110783661B - Battery pack

Info

Publication number: CN110783661B
Application number: CN201910669944.0A
Authority: CN
Inventors: 赵璟镐; 金润吉; 金埈煐; 睦旻均
Original assignee: Samsung SDI Co Ltd
Current assignee: Samsung SDI Co Ltd
Priority date: 2018-07-25
Filing date: 2019-07-24
Publication date: 2023-06-16
Anticipated expiration: 2039-07-24
Also published as: CN110783661A; KR20200011816A; US11349178B2; US20200035975A1

Abstract

There is provided a battery pack including: a plurality of battery cells arranged such that main surfaces thereof face each other; and a partition wall between adjacent battery cells. The partition wall includes at least one air pocket having a concave shape in a direction away from a main surface of one of the adjacent battery cells in a thickness direction of the partition wall.

Description

Battery pack

Korean patent application No. 10-2018-0086762, entitled "battery pack" filed on 25 th 7 th 2018, to the korean intellectual property office, is incorporated herein by reference in its entirety.

Technical Field

Embodiments relate to a battery pack.

Background

In general, secondary batteries are rechargeable, unlike primary batteries. The secondary battery may be used as an energy source for mobile devices, electric vehicles, hybrid vehicles, electric bicycles, uninterruptible power supplies, etc., and may be used in the form of a single battery cell or a battery pack in which a plurality of battery cells are combined into one unit, depending on the type of external device to which the secondary battery is applied.

A small mobile device (such as a mobile phone) may operate for a certain time according to the output and capacity of a single battery; however, in the case of long-time driving or high-power driving (such as in the case of an electric vehicle or a hybrid vehicle having high power consumption), a battery pack may be preferable due to output and capacity problems. The battery pack may increase the output voltage or the output current according to the number of built-in battery cells.

Disclosure of Invention

Embodiments relate to a battery pack including a plurality of battery cells arranged such that main surfaces thereof face each other and including a partition wall between adjacent battery cells. The partition wall includes at least one air pocket having a concave shape in a direction away from a main surface of one of the adjacent battery cells in a thickness direction of the partition wall.

The at least one air pocket may have a closed form that hermetically accommodates an air layer having a volume corresponding to the at least one air pocket with the main surface of the battery cell.

The at least one air pocket may include a pair of air pockets located at symmetrical positions facing each other in a thickness direction of the partition wall with the partition wall therebetween. A pair of air pockets may be located between two adjacent battery cells with a dividing wall therebetween.

The pair of air pockets may be isolated from each other by a partition wall and may not be connected to each other.

The at least one air pocket may comprise: a first wall spaced apart from a major surface of the battery cell; and a second wall protruding from the first wall toward the main surface of the battery cell and contacting the main surface of the battery cell.

The first and second walls of the at least one air pocket and the major surface of the battery cell may form an enclosed space to be isolated from the outside.

The partition wall may include: a thin-walled portion having a relatively small thickness to be spaced apart from the main surface of the battery cell; and a thick-walled portion having a relatively large thickness to contact the main surface of the battery cell.

The thin-walled portions and the thick-walled portions may be formed at alternating positions in one direction through the partition wall.

The first wall of the at least one air pocket may be provided by a thin-walled portion of the dividing wall. The second wall of the at least one cavitation may be provided by a thick-walled portion of the dividing wall.

The at least one air pocket may comprise a plurality of air pockets along a wall surface of the dividing wall. The plurality of air pockets may be in isolated form such that different air pockets are not connected to each other.

The at least one air pocket may comprise a plurality of air pockets along a wall surface of the partition wall in a matrix form comprising a plurality of rows and a plurality of columns.

The at least one air pocket may include a plurality of air pockets that are regularly repeated in a pattern unit in a specific shape along a wall surface of the partition wall.

The pattern units may have an isolated form such that different pattern units are not connected to each other.

The plurality of air pockets may be in the form of a matrix in the form of a dot pattern unit, the matrix comprising a plurality of rows and a plurality of columns.

The diameter of the at least one air pocket may be greater than the distance between adjacent air pockets.

The partition wall may include: a main region in which a plurality of air pockets are arranged; and a boundary region surrounding the main region, the boundary region being free of air pockets therein.

The boundary region may include: and a sealing portion surrounding and sealing the main area.

The sealing portion may contact the major surfaces of adjacent battery cells facing each other.

The sealing portion may be in the form of a closed loop completely surrounding the main area.

The battery cell may include: a terminal surface on which an electrode terminal is formed; a bottom surface opposite the terminal surface; and a side surface connecting the terminal surface to the bottom surface and having a relatively smaller area than the main surface. The battery pack may further include: a first flange portion protruding from the partition wall toward the battery cell to cover the terminal surface; a second flange portion protruding from the partition wall toward the battery cell to cover the bottom surface; and a third flange portion protruding from the partition wall toward the battery cell to cover the side surface.

The sealing portion may completely surround the main region between the main region and the first to third flange portions.

Drawings

Features will become apparent to those skilled in the art from the detailed description of an exemplary embodiment with reference to the accompanying drawings, in which:

fig. 1 illustrates an exploded perspective view of a battery pack according to an embodiment;

fig. 2 shows an exploded perspective view of a portion of the battery pack shown in fig. 1;

FIG. 3 shows a perspective view of the frame shown in FIG. 1;

FIG. 4 illustrates a plan view of a portion of the frame shown in FIG. 3;

FIG. 5 illustrates an enlarged perspective view of a portion of the frame illustrated in FIG. 3;

FIG. 6 shows a cross-sectional view of the frame shown in FIG. 3;

FIG. 7 illustrates a cross-sectional view of a portion of the frame illustrated in FIG. 6;

FIG. 8 shows a plan view of the frame shown in FIG. 3;

FIG. 9 illustrates a cross-sectional view of a portion of the frame illustrated in FIG. 3; and

fig. 10 shows a cross-sectional view showing a frame according to the modified embodiment of fig. 9.

Detailed Description

Example embodiments will now be described more fully hereinafter with reference to the accompanying drawings; however, they may be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the exemplary embodiments to those skilled in the art.

In the drawings, the size of layers and regions may be exaggerated for clarity of illustration. It will also be understood that when a layer or element is referred to as being "on" another layer or substrate, it can be directly on the other layer or substrate, or intervening layers may also be present. Further, it will be understood that when a layer is referred to as being "under" another layer, the layer can be directly under the other layer or one or more intervening layers may also be present. Further, it will also be understood that when a layer is referred to as being "between" two layers, the layer may be the only layer between the two layers, or one or more intervening layers may also be present. Like reference numerals refer to like elements throughout.

Reference will now be made in detail to the embodiments, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout. In this regard, the embodiments presented may take different forms and should not be construed as limited to the descriptions set forth herein. Accordingly, the embodiments are described below merely to explain aspects of the present description by referring to the figures.

Fig. 1 illustrates an exploded perspective view of a battery pack according to an embodiment. Fig. 2 shows an exploded perspective view of a portion of the battery pack shown in fig. 1. Fig. 3 shows a perspective view of the frame shown in fig. 1.

Referring to the drawings together, the battery pack may include a plurality of battery cells B arranged in a first direction (Z1 direction) and a plurality of frames F arranged in the first direction (Z1 direction) together with the battery cells B, the frames F being positioned between the battery cells B. For example, the frames F may be arranged in one direction (Z1 direction), wherein adjacent frames F may be coupled to face each other with the battery cell B therebetween.

The frame F may be positioned between the neighboring battery cells B to block electrical and thermal interference between the neighboring battery cells B. For example, the frame F may include a receiving portion FA for receiving different battery cells B on both sides of a partition wall (partition wall) W between adjacent battery cells B. For example, the frame F may define a receiving part FA surrounding the periphery of the battery cell B to receive the battery cell B and to receive the battery cell B while extending along the contour of the battery cell B.

For example, the frame F may include partition walls W between adjacent battery cells B in the first direction (Z1 direction) for blocking electrical and thermal interference between the adjacent battery cells B, and flange portions FU, FL, and FS (see fig. 2) protruding from the partition walls W toward the battery cells B in the first direction through (across) the top, bottom, left, and right sides of the battery cells B, and extending along the outline of the battery cells B.

The battery cell B may include: a terminal surface U, a bottom surface L, a pair of main surfaces M and a pair of side surfaces S, the terminal surface U extending in a second direction (X1 direction), an electrode terminal E being formed on the terminal surface U, the bottom surface L being opposite to the terminal surface U in a third direction (Y1 direction), the pair of main surfaces M having relatively large areas in the second direction and the third direction, the terminal surface U being connected to the bottom surface L, the pair of side surfaces S having relatively small areas, and extending in the third direction (Y1 direction), the terminal surface U being connected to the bottom surface L. The battery cell B may be formed in a substantially rectangular parallelepiped shape including a terminal surface U, a bottom surface L, a pair of main surfaces M, and a pair of side surfaces S. The term "main surface M" means a surface occupying the largest area among the outer surfaces of the battery cells B. When a plurality of battery cells B are arranged in the first direction (Z1 direction), the main surfaces M of the neighboring battery cells B may be arranged to face each other in the first direction. In this case, the partition wall W of the frame F may be located between the main surfaces M of the adjacent battery cells B, and the flange portions FU, FL, and FS (see fig. 2) of the frame F may protrude from the partition wall W in the first direction and cover the outer circumferences of the adjacent battery cells B (e.g., overlap with the outer surfaces of the battery cells B other than the main surfaces M). For example, the flange parts FU, FL, and FS may include a first flange part FU protruding from the partition wall W toward the battery cell B in the first direction and extending in the second direction X1 to cover the terminal surface U of the battery cell B, a second flange part FL protruding from the partition wall W toward the battery cell B in the first direction and extending in the second direction X1 to cover the bottom surface L of the battery cell B, and a third flange part FS protruding from the partition wall W toward the battery cell B in the first direction and extending in the third direction Y1 to cover the side surface S of the battery cell B.

Fig. 4 shows a plan view of a portion of the frame shown in fig. 3. Fig. 5 shows an enlarged perspective view of a portion of the frame shown in fig. 3. Fig. 6 shows a cross-sectional view of the frame shown in fig. 3. Fig. 7 shows a cross-sectional view of a portion of the frame shown in fig. 6.

Referring to fig. 5, at least one air pocket (air pocket) a recessed with respect to the battery cell B in the thickness or first direction (Z1 direction) of the partition wall W may be formed in the partition wall W. The air pocket a may be formed by a suitable method. For example, the air pocket a may be formed by engraving the partition wall W. The air pocket a may form an air layer in a stationary state, which is substantially non-flowing and is hermetically restricted. For example, the air pocket a may hermetically accommodate an air layer of a volume corresponding to the air pocket a together with the main surface M of the battery cell B.

The description of the recess of the air pocket a shows that the air pocket a has a relatively small thickness away from the main surface M of the battery cell B in the thickness direction (Z1 direction) of the partition wall W, thereby forming an empty space between the partition wall W and the main surface M of the battery cell B. The air pocket a may be a recess for hermetically accommodating an air layer therein.

For example, unlike the air pocket a, the shape protruding convexly from the wall surface of the partition wall W toward the main surface M of the battery cell B may provide a certain space between the wall surface of the partition wall W and the main surface M of the battery cell B, and an air layer may be formed between the wall surface of the partition wall W and the main surface M of the battery cell B, but may not hermetically accommodate the air layer. For example, between the wall surface of the partition wall W and the main surface M of the battery cell B, a protruding shape (protruding shape) protruding convexly from the wall surface of the partition wall W toward the main surface M of the battery cell B may not isolate an air layer from the outside, and may not hermetically accommodate the air layer.

On the other hand, the air pocket a having a shape recessed from the wall surface of the partition wall W in a direction away from the main surface M of the battery cell B in the thickness direction (Z1 direction) of the partition wall W can hermetically accommodate the air layer while surrounding the volume of the air layer corresponding to the air pocket a together with the main surface M of the battery cell B, and can isolate the air layer from the outside. In this case, the air pocket a may be recessed in a direction away from the main surface M of the battery cell B in the thickness direction (Z1 direction) of the partition wall W.

The air pocket a may have a concave shape to surround an air layer therein. For example, the air pocket a may define a space together with the main surface M of the battery cell B, and may define an enclosed space isolated from the outside. In an embodiment, the air pockets a may be formed in plurality along the wall surface of the partition wall W (e.g., in the second direction and the third direction). Each air pocket a may define a space and define an enclosed space isolated from the outside. The closed space defined by the air pocket a may form a space that is substantially isolated from the outside and not connected to the outside. Thus, the air layer surrounded by the air pocket a may not substantially flow in or out from the outside of the air pocket a, and may be restricted in a stationary state by the air pocket a. For example, the air layer surrounded by air pocket a may be maintained in a stationary state with its average flow rate substantially near zero, and even when the air layer of air pocket a has an air flow due to thermal imbalance, its movement may be limited by being surrounded by the narrow size of the air pocket. The cavitation a may be at rest with an average flow rate substantially near zero and may have random motion. For example, air pocket A does not form a certain pattern of air flow.

The air pocket a may be formed to have a sufficiently narrow size to restrict the flow of the air layer limited by the air pocket a. Air pockets of narrow dimensions (for example, narrow dimensions along all three directions X1, Y1, and Z1) may be formed in plurality along the wall surface of the partition wall W. In this way, by forming the air pocket a of a narrow size in plurality, thermal interference between the two battery cells B facing each other with the partition wall W therebetween can be suppressed.

If there is no limitation on the size of the air pocket a, that is, if the air pocket a having an excessively large size is formed, convective heat transfer is promoted because an air flow (such as natural convection) is formed in the air pocket a due to thermal unbalance. Therefore, heat flow between the adjacent battery cells B may be enhanced, so that heat insulation between the adjacent battery cells B may not be performed. But rather heat transfer is performed between them.

In contrast, according to the embodiment, by forming the plurality of air pockets a separated by a narrow size between two adjacent battery cells B with the partition wall W therebetween, the air layer of the air pockets a may be restricted to a substantially stationary state (e.g., restricted to a stationary state in which the average flow rate is close to zero), heat insulation may be performed between the adjacent battery cells B, and thermal interference may be blocked between the adjacent battery cells B.

The air pockets a may be formed in plural along the wall surface of the partition wall W. For example, the air pockets a may be formed in a regular pattern along the wall surface of the partition wall W. As an example, the air pockets a may be arranged in a matrix form having a plurality of rows and a plurality of columns along the wall surface of the partition wall W. In an embodiment, the air pockets a may be formed in a dot pattern arranged in a matrix form. For example, the air pockets a may be arranged in a matrix form having a plurality of rows and a plurality of columns along the wall surface of the partition wall W in a dot pattern unit.

The air pockets a may be formed in plural along the wall surface of the partition wall W. The plurality of air pockets a may be densely arranged along the wall surface of the partition wall W. The air pockets a may be formed in isolated form not connected to each other. For example, the air pockets a may be separated from each other along the second direction X1 and the third direction Y1, and no fluid connection is formed between adjacent air pockets a. Each air pocket a may hermetically accommodate a volume of air layer corresponding to each air pocket a and isolate the air layer from the outside. Thus, each air pocket a may have a closed form of isolation shape, and no fluid connection may be formed between adjacent air pockets a.

For example, when a plurality of air pockets a are formed in a dot pattern along the wall surface of the partition wall W, the unit dots forming each air pocket a may have a closed form of isolation shape. In another embodiment, the plurality of air pockets a may be formed in various patterns other than the dot pattern along the wall surface of the partition wall W as long as the shape of the pattern unit of the pattern-forming unit may have a closed form of isolation shape. For example, in another embodiment, the pattern unit may have a round shape (e.g., an oval shape other than a round shape), or may have an angular shape (e.g., a square shape). In the embodiment, unlike the angular shape, when the wall surface of the partition wall W and the main surface M of the battery cell B are in close contact with each other, the air pockets a formed in the dot pattern may prevent physical damage to the main surface M of the battery cell B, and since the air pockets a do not have directionality in a specific direction (i.e., such as an oval shape, a major axis direction, or a minor axis direction), the air layers of the air pockets a may also be restricted to a stationary state without consideration of directionality.

For example, according to a specific design, the air pockets a formed in a dot pattern along the wall surface of the partition wall W may be formed in a cylindrical shape or a dome shape in the thickness direction (Z1 direction) of the partition wall W. In the embodiment shown in fig. 5, the air pocket a may be formed in a cylindrical shape, and the air layer may be confined in the cylindrical shape.

The air pocket a may be formed in a concave shape to hermetically accommodate an air layer of a volume corresponding to the air pocket a together with the main surface M of the battery cell B. For example, each air pocket a may include a first wall A1 spaced apart from the major surface M of the battery cell B and a second wall A2 protruding from the first wall A1 toward the battery cell B. Each air pocket a may accommodate an air layer corresponding to the volume defined by the first and second walls A1 and A2 of the air pocket a and the major surface M of the battery cell B.

In an embodiment, the first wall A1 may be formed in a circular shape according to a dot pattern, and the second wall A2 may protrude from the first wall A1 toward the main surface M of the battery cell B in the thickness direction (Z1 direction) of the partition wall W. Therefore, the air pocket a defined by the first wall A1 and the second wall A2 may contact the main surface M of the battery cell B, form a closed space of a cylindrical shape, and accommodate an air layer of a cylindrical shape.

Referring to fig. 7, the partition wall W may include a thin-walled portion W11 and a thick-walled portion W12 having different thicknesses t1 and t2, respectively. In this case, the first wall A1 (e.g., the rear wall) of the air pocket a may be provided by the thin-walled portion W11, and the second wall A2 (e.g., the side wall of the air pocket a) may be provided by the thick-walled portion W12. In this way, the first wall A1 and the second wall A2 of the air pocket a may be provided by the thin-walled portion W11 and the thick-walled portion W12 having different thicknesses t1 and t2, and the first wall A1 and the second wall A2 may hermetically accommodate an air layer therein together with the main surface M of the battery cell B.

For example, the thin-walled portion W11 may be formed to a relatively small thickness t1 to be spaced apart from the main surface M of the battery cell B, and a first wall A1 of the air pocket a spaced apart from the main surface M of the battery cell B may be provided. The thick-walled portion W12 may be formed to a relatively large thickness t2 to contact the main surface M of the battery cell B and provide a second wall A2 of the air pocket a that contacts the main surface M of the battery cell B.

The second wall A2 of the air pocket a may extend from the first wall A1 toward the main surface M of the battery cell B and may contact the main surface M of the battery cell B. The air pocket a may isolate the air layer from the outside by a second wall A2 extending from the first wall A1 toward the battery cell B and contacting the main surface M of the battery cell B. Thus, by isolating the air layer by the first and second walls A1 and A2 of the air pocket a and the main surface M of the battery cell B, an air layer in a stationary state that does not substantially flow can be formed. By forming the air layer in a stationary state in which the average flow velocity is close to zero, heat transfer due to natural convection accompanying the air flow can be suppressed to the maximum. If the air layer contained in the air pocket a flows in or out from the outside to form an air flow, heat transfer will occur with the air flow. Accordingly, the heat insulating effect between two adjacent battery cells B with air pockets a therebetween is correspondingly reduced.

The air pockets a may be formed in pairs at symmetrical positions facing each other in the thickness direction (Z1 direction) of the partition wall W with the partition wall W therebetween. In this case, the pair of air pockets a facing each other may be isolated from each other by the partition wall W and may not be connected to each other. If a pair of air pockets a facing each other are directly connected to each other, the adjacent battery cells B may be directly connected to each other through the pair of air pockets a connected to each other, and electrical insulation between the adjacent battery cells B cannot be ensured. The partition wall W according to the embodiment may provide electrical insulation between the battery cells B adjacent to each other with the partition wall W therebetween. The partition wall W may also be located between the pair of air pockets a facing each other to maintain the insulating function of the partition wall W between the pair of air pockets a facing each other so that the pair of air pockets a facing each other are not directly connected to each other.

In this way, the air pockets a may be formed in pairs at symmetrical positions facing each other with the partition wall W therebetween. A pair of air pockets a may be located between two battery cells B adjacent to each other with a partition wall W therebetween. In other words, the air pocket a may be formed for each of the two receiving parts FA for receiving each of the two battery cells B adjacent to each other with the partition wall W therebetween. A pair of air pockets a formed in the respective receiving parts FA may be located between two adjacent battery cells B.

The partition wall W may include a thin-walled portion W11 and a thick-walled portion W12 having different thicknesses t1 and t2. In this case, a pair of air pockets a respectively facing the adjacent battery cells B may be formed at the position of the thin-walled portion W11, and the thick-walled portion W12 at the position adjacent to the thin-walled portion W11 may surround the outer circumference of the air pockets a and restrict the air layer thereof.

The thin-walled portions W11 and the thick-walled portions W12 of the partition wall W may be formed at adjacent positions, and the thin-walled portions W11 and the thick-walled portions W12 may be formed at alternating positions in one direction through (across) the partition wall W. For example, the partition wall W may be formed in a substantially rectangular shape including a pair of long sides and a pair of short sides, in which case the thin-walled portions W11 and the thick-walled portions W12 may be formed at alternating positions in the long-side direction of the partition wall W, and the thin-walled portions W11 and the thick-walled portions W12 may be formed at alternating positions in the short-side direction of the partition wall W. In this way, when the thin-walled portions W11 and the thick-walled portions W12 are formed at alternating positions, the air pocket a may be located at the position of the thin-walled portion W11 spaced apart from the main surface M of the battery cell B, and the air pocket a of a closed form may be formed at the position of the thick-walled portion W12 adjacent to the thin-walled portion W11 while contacting the main surface M of the battery cell B.

Referring to fig. 4, the air pocket a may be formed in a narrow size to suppress natural convection, and may be formed in a plurality along the wall surface of the partition wall W. In this way, when a plurality of air pockets a spaced apart in a narrow size are densely formed between the adjacent battery cells B, heat transfer caused by natural convection between the adjacent battery cells B can be suppressed. For example, the largest dimension of each air pocket a (e.g., the diameter d1 of one dot constituting a pattern unit among dot patterns forming the air pocket a) may be larger than the distance between adjacent air pockets a (e.g., the distance d2 between adjacent air pockets). For example, by closely and densely arranging the adjacent air pockets a, the heat insulating effect between the adjacent battery cells B can be further enhanced. For example, the thick-walled portion W12 of the partition wall W corresponding to the distance d2 between the adjacent air pockets a may surface-contact the adjacent battery cells B between the adjacent battery cells B to cause heat conduction between the adjacent battery cells B. Thus, the diameter d1 of an air pocket a may be greater than the distance d2 between adjacent air pockets a.

According to the present disclosure, even when the thick-walled portion W12 of the partition wall W corresponding to the distance d2 between the adjacent air pockets a causes heat conduction between the battery cells B, this may be accompanied by the purpose of forming the air pockets a of a closed shape to hermetically accommodate the air layer. Thus, the thick-walled portion W12 contacts the main surface M of the battery cell B. In comparison with the heat insulating effect of the air pockets a by forming the diameter d1 of the air pockets a to be larger than the distance d2 between the adjacent air pockets a, even when heat conduction is inevitably involved by the thick-walled portion W12 in contact with the main surface M of the battery cell B, the heat conducting effect of the thick-walled portion W12 can be controlled to be below an appropriate level.

In an embodiment, the air pocket a may be formed in a dot shape. The distance d2 between adjacent air pockets a may be measured differently along the outer circumference of air pocket a. In an embodiment, the minimum distance between adjacent air pockets a (i.e., the distance d2 between the curved portions of adjacent air pockets a) may be smaller than the diameter d1 of air pocket a, and even the maximum distance between adjacent air pockets a may be smaller than the diameter d1 of air pocket a.

In the embodiment shown in fig. 7, when the thick-walled portion W12 of the partition wall W is in contact with the main surfaces M of the two battery cells B facing each other with the partition wall W therebetween, the position of the partition wall W can be stably maintained between the two battery cells B.

Fig. 8 is a plan view of the frame shown in fig. 3. Fig. 9 is a cross-sectional view of a portion of the frame shown in fig. 3.

Referring to fig. 8, the partition wall W may include a main area W1 in which a plurality of air pockets a are densely located and a boundary area W2 surrounding the main area W1. The air pocket a may not be formed in the boundary region W2. The main region W1 of the partition wall W may correspond to a central region of the battery cell B, and the boundary region W2 of the partition wall W may correspond to a position of the battery cell B near the terminal surface U, the bottom surface L, and the side surface S (i.e., near an edge region of the outside of the battery cell B). Since heat accumulation occurs more easily in the central region of the battery cell B than in the boundary region relatively close to the outside of the battery cell B, in order to block thermal runaway from some locally deteriorated battery cells B to neighboring battery cells B due to the heat accumulation, a plurality of air pockets a may be located in the main region W1 of the partition wall W corresponding to the central region of the battery cell B. Further, since the central regions of the battery cells B may be curvedly expanded due to expansion, the central regions of the neighboring battery cells B may be deformed in directions approaching each other, a plurality of air pockets a may be located in the main region W1 of the partition wall W corresponding to the central regions of the battery cells B to provide heat insulation between the neighboring battery cells B. Unlike the main region W1 of the partition wall W, since the insulation between adjacent battery cells B provided in the boundary region W2 is relatively small, the air pocket a may be omitted from the boundary region W2 of the partition wall W. For example, even if the air pocket a is formed in the boundary region W2 of the partition wall W, when the central region of the battery cell B is curvedly expanded due to expansion, the air pocket a formed in the boundary region W2 of the partition wall W may be separated from the main surface M of the battery cell B, thereby losing the function of the air pocket a. For ease of manufacture, the air pocket a may be omitted in the boundary region W2 of the partition wall W.

Referring to fig. 9, a sealing portion W21 for sealing the central main area W1 may be formed in the boundary area W2. The sealing part W21 may be formed relatively thick to closely contact the main surface M of the neighboring battery cell B in the thickness direction (Z1 direction) of the partition wall W. In an embodiment, the thickness t3 of the sealing portion W21 formed in the boundary region W2 may be equal to the thickness t2 of the thick-walled portion W12 formed in the main region W1. When the thickness t3 of the sealing portion W21 of the boundary region W2 is equal to the thickness t2 of the thick-walled portion W12 of the main region W1, the main surfaces M of the two battery cells B adjacent to each other with the partition wall W therebetween may be in contact with the sealing portion W21 in the boundary region W2 of the partition wall W and in contact with the thick-walled portion W12 in the main region W1 of the partition wall W. In the air pocket a formed in the main area W1, an air layer may be hermetically accommodated in the air pocket a by the thick-walled portion W12. The air layer hermetically contained in the air pocket a may be fluidly isolated from the outside air of the partition wall W by the sealing portion W21 of the boundary region W2. In this way, the air layer in the air pocket a can be doubly hermetically accommodated due to the thick-walled portion W12 of the main region W1 and the sealing portion W21 of the boundary region W2, and can be doubly isolated from the outside of the partition wall W to provide heat insulation between two battery cells B adjacent to each other with the partition wall W therebetween in a stationary state where the air flow is not substantially formed.

The sealing portion W21 may contact the main surfaces M of the adjacent battery cells B at symmetrical positions of the partition wall W in the thickness direction (Z1 direction) of the partition wall W, and may closely contact the main surfaces M of the two adjacent battery cells B. The sealing part W21 may closely contact the two battery cells B facing each other with the partition wall W therebetween, thereby isolating the main region W1 of the partition wall W from the outside of the partition wall W while sealing the main region W1 of the partition wall W. Here, the description of the sealing portion W21 sealing the main area W1 or isolating the main area W1 from the outside of the partition wall W may indicate: between the main area W1 and the outside of the partition wall W, fluid connection is blocked, and fluid flow (such as penetration of outside air into the main area W1 in which the plurality of air pockets a are formed or outflow of air layers hermetically contained by the plurality of air pockets a to outside air) is blocked, thereby blocking fluid connection between the outside of the partition wall W and the main area W1 in which the plurality of air pockets a are formed.

The sealing portion W21 may surround the main area W1 in which the plurality of air pockets a are densely arranged. The sealing portion W21 may isolate a set of air pockets a disposed in the main area W1 from the outside of the partition wall W. By isolating the set of air pockets a from the exterior of the partition wall W, the sealing portion W21 may block the air flow between the exterior of the partition wall W and the main area W1 and block the fluid connection between the exterior of the partition wall W and the main area W1. Heat transfer due to natural convection (such as inflow of air from outside of the partition wall W or outflow of air to outside of the partition wall W) of the air flow connected to the main area W1 can be reduced or prevented.

By isolating the main area W1 in which the group of air pockets a is arranged from the outside of the partition wall W, the sealing portion W21 can prevent inflow of air from the outside to the main area W1 or outflow of air from the main area W1 to the outside, and an air layer in a stationary state in which substantially no air flow is formed can be formed in the main area W1.

Referring to fig. 9, the boundary region W2 of the partition wall W may include a sealing portion W21 and an extension portion W22, the sealing portion W21 being formed relatively thick (e.g., slightly thicker than the thick-walled portion W12) in the thickness direction or first direction (Z1 direction) of the partition wall W to closely contact the main surface M of the battery cell B, and the extension portion W22 being formed relatively thinner than the sealing portion W21 in the thickness direction or first direction (Z1 direction) of the partition wall W to be spaced apart from the main surface M of the battery cell B. The extension portion W22 may connect the sealing portion W21 of the boundary region W2 to the air pocket a of the main region W1, and may form a varying thickness t4 while extending obliquely in the thickness direction (Z1 direction) of the partition wall W from the sealing portion W21 contacting the main surface M of the battery cell B. The extension W22 may help prevent damage to the main surface M of the battery cell B.

Referring to fig. 8, the sealing portion W21 may entirely surround the main area W1. The main region W1 may be surrounded by the sealing portion W21, and may not be exposed from the sealing portion W21. For example, the sealing portion W21 may be formed in a closed form or a closed loop form in the second direction X1 and the third direction Y1 to completely surround the main area W1, and may not be formed in an open loop form in which some portion is opened.

The sealing portion W21 may surround the main area W1 between the main area W1 and the first, second and third flange portions FU, FL and FS to seal the main area W1. More specifically, the frame F including the partition wall W may include: a first flange portion FU protruding from the partition wall W in the first direction Z1 and extending in the second direction X1 to cover the terminal surface U of the battery cell B; a second flange portion FL protruding from the partition wall W in the first direction Z1 and extending in the second direction X1 to cover the bottom surface L of the battery cell B; and a third flange portion FS protruding from the partition wall W in the first direction Z1 and extending in the third direction Y1 to cover the side surface S of the battery cell B. The sealing portion W21 may completely surround the main area W1 between the main area W1 and the first, second and third flange portions FU, FL and FS.

Referring to fig. 9, according to the present disclosure, the air pocket a may have a recessed shape with respect to the main surface M of the battery cell B in the thickness direction (Z1 direction) of the partition wall W. The sealing portion W21 may be formed to closely contact the main surface M of the battery cell B in the thickness direction (Z1 direction) of the partition wall W while surrounding the main region W1 where the air pocket a is formed, thereby minimizing thermal interference between two adjacent battery cells B with the partition wall W therebetween.

Fig. 10 is a sectional view showing a frame according to the modified embodiment of fig. 9. Referring to fig. 10, a sealing portion W21 for sealing the central main area W1 may be formed in the boundary area W2. The sealing part W21 may be formed relatively thick to closely contact the main surface M of the neighboring battery cell B in the thickness direction (Z1 direction) of the partition wall W.

In the embodiment shown in fig. 10, the thickness t3 of the sealing portion W21 formed in the boundary region W2 may be greater than the thickness t2 of the thick-walled portion W12 formed in the main region W1. In the embodiment shown in fig. 9, the thickness t3 of the seal portion W21 formed in the boundary region W2 is equal to the thickness t2 of the thick-wall portion W12 formed in the main region W1. However, in the embodiment shown in fig. 10, the thickness t3 of the sealing portion W21 formed in the boundary region W2 may be greater than the thickness t2 of the thick-walled portion W12 formed in the main region W1. In the embodiment of fig. 9 and 10, the thickness t3 of the sealing portion W21 of the boundary region W2 in the present disclosure may be at least equal to or greater than the thickness t2 of the thick-walled portion W12 of the main region W1. The extension portion W22 between the portions having the thickness t2 and the thickness t3 may have a variable thickness t4 thinned between the portion having the thickness t3 and the portion having the thickness t2.

Further, in the embodiment of fig. 10, the main surfaces M of the battery cells B adjacent to each other on both sides with the partition wall W therebetween may contact the sealing portion W21 in the boundary region W2 and may contact the thick-walled portion W12 in the main region W1. For example, when the main surface M of the battery cell B expands in the thickness direction (Z1 direction) of the partition wall W according to the expansion of the battery cell B, the center region of the battery cell B facing the main region W1 among the main surface M of the battery cell B flexibly expands while protruding toward the partition wall W. Even if the sealing portion W21 of the boundary region W2 and the thick-walled portion W12 of the main region W1 are formed to different thicknesses t3 and t2, the boundary region of the battery cell B facing the boundary region W2 among the main surfaces M of the battery cell B does not protrude toward the partition wall W or protrudes to a relatively small extent. The main surface M of the battery cell B curvedly expanded in the central region may contact both the thick-walled portion W12 of the main region W1 and the sealing portion W21 of the boundary region W2. For example, the center region of the main surface M of the battery cell B may be curvedly expanded due to the expansion of the battery cell B to contact the thick-walled portion W12 of the main region W1. The boundary region of the main surface M of the battery cell B may contact the sealing portion W21 of the boundary region W2 formed to be relatively thick even without protruding toward the partition wall W due to the expansion of the battery cell B.

By summarizing and reviewing, by forming a plurality of air pockets for hermetically accommodating an air layer between adjacent battery cells, effective heat insulation can be provided between the adjacent battery cells, and thermal interference between the adjacent battery cells can be blocked. By effectively insulating adjacent cells from each other, thermal runaway from some locally degraded cells to other adjacent cells may be blocked.

Example embodiments have been disclosed herein, and although specific terms are employed, they are used and are to be interpreted in a generic and descriptive sense only and not for purpose of limitation. In some cases, features, characteristics, and/or elements described in connection with a particular embodiment may be used alone or in combination with features, characteristics, and/or elements described in connection with other embodiments unless specifically indicated otherwise as would be apparent to one of ordinary skill in the art at the time of filing the present application. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as set forth in the appended claims.

Claims

1. A battery pack, the battery pack comprising:

a plurality of battery cells arranged such that main surfaces thereof face each other; and

a plurality of frames, each of the plurality of battery cells being surrounded by adjacent frames of the plurality of frames to be received between the adjacent frames,

wherein each of the plurality of frames includes a partition wall including a plurality of air pockets formed in an isolated form not connected to each other along a wall surface of the partition wall, and

each of the plurality of air pockets has a concave shape in a direction away from the main surface of one of the adjacent battery cells in the thickness direction of the partition wall,

wherein the partition wall includes: a main region in which the plurality of air pockets are disposed; and a boundary region surrounding the main region, in which no air pocket is formed, the boundary region including a sealing portion surrounding the main region and sealing the main region, and an extension portion connecting the sealing portion of the boundary region to the air pocket of the main region, the extension portion being formed relatively thinner than the sealing portion in a thickness direction of the partition wall to be spaced apart from the main surface of the battery cell.

2. The battery pack of claim 1, wherein:

each of the plurality of air pockets has a closed form that hermetically accommodates an air layer having a volume corresponding to the air pocket with the main surface of the battery cell.

3. The battery pack of claim 1, wherein:

the plurality of air pockets include air pocket pairs located at symmetrical positions facing each other in a thickness direction of the partition wall with the partition wall therebetween, an

A pair of air pockets is located between two adjacent battery cells with a partition wall therebetween.

4. The battery pack of claim 3, wherein:

the pair of air pockets are isolated from each other by a partition wall and are not connected to each other.

5. The battery pack of claim 1, wherein:

each of the plurality of air pockets includes: a first wall spaced apart from a major surface of the battery cell; and a second wall protruding from the first wall toward the main surface of the battery cell and contacting the main surface of the battery cell.

6. The battery pack of claim 5, wherein:

the first and second walls of each of the plurality of air pockets and the major surface of the battery cell form an enclosed space to be isolated from the outside.

7. The battery pack of claim 5, wherein:

the partition wall includes:

a thin-walled portion having a relatively small thickness to be spaced apart from the main surface of the battery cell; and

thick-walled portions having a relatively large thickness to contact the major surfaces of the battery cells.

8. The battery pack of claim 7, wherein:

the thin-walled portions and the thick-walled portions are formed at alternating positions in one direction through the partition wall.

9. The battery pack of claim 7, wherein:

the first wall of each of the plurality of air pockets is provided by a thin wall portion of the dividing wall, and

the second wall of each of the plurality of pockets is provided by a thick-walled portion of the dividing wall.

10. The battery pack of claim 1, wherein:

the plurality of air pockets are in a matrix form along a wall surface of the partition wall, the matrix form including a plurality of rows and a plurality of columns.

11. The battery pack of claim 1, wherein:

the plurality of air pockets are regularly repeated in a pattern unit of a specific shape along the wall surface of the partition wall.

12. The battery pack of claim 11, wherein:

the pattern units have an isolated form such that the different pattern units are not connected to each other.

13. The battery pack of claim 11, wherein:

the plurality of air pockets are in a matrix form in a dot pattern unit, the matrix form including a plurality of rows and a plurality of columns.

14. The battery pack of claim 13, wherein:

each of the plurality of air pockets has a diameter that is greater than a distance between adjacent air pockets of the plurality of air pockets.

15. The battery pack of claim 1, wherein:

the sealing portion contacts the major surfaces of adjacent battery cells facing each other.

16. The battery pack of claim 1, wherein:

the sealing portion is in the form of a closed loop completely surrounding the main area.

17. The battery pack of claim 1, wherein:

the battery cell includes: a terminal surface on which an electrode terminal is formed; a bottom surface opposite the terminal surface; and a side surface connecting the terminal surface to the bottom surface and having a relatively smaller area than the main surface, an

The battery pack further includes: a first flange portion protruding from the partition wall toward the battery cell to cover the terminal surface;

a second flange portion protruding from the partition wall toward the battery cell to cover the bottom surface; and

and a third flange portion protruding from the partition wall toward the battery cell to cover the side surface.

18. The battery pack of claim 17, wherein:

the sealing portion completely surrounds the main region between the main region and the first to third flange portions.